BIOTIN IS TRADITIONALLY CONSIDERED TO BE A VITAMIN B SUBSTANCE. IT IS AN ESSENTIAL COENZYME IN FAT METABOLISM AND IN OTHER CARBOXYLATION REACTIONS. ITS DEFICIENCY, AN INHERITED METABOLIC DISORDER OR MAY OCCUR AFTER CONSUMING RAW EGGS AS EGG WHITE CONTAINS A HEAT LABILE PROTEIN,AVIDIN WHICH COMBINES VERY TIGHTLY WITH BIOTIN PREVENTING ITS ABSORPTION.DEFICIENCY OF BIOTIN MAY CAUSE DEPRESSION,HALLUCINATIONS,MUSCLE PAIN AND DERMATITIS,ALOPECIA,SEBORRHEIC DERMATITIS,ANOREXIA AND GLOSSITIS.